The price threshold lift for eligible houses is part of a suite of changes the Government has unleashed in a bid to tip the scales towards first-home buyers.
Data from OneRoof shows it is within grasp in Christchurch, where existing homes in Addington, Bishopdale, Sydenham and Richmond all fall under the cap.
Phillipstown takes the crown for the cheapest spot in the city, where the median house price is $350,000.
Harcourts New Zealand chief operating officer Daniel Coulson said it could be done.
He told Newstalk ZB the median house price in Christchurch was about $560,000 - just a shade above the existing cap for a new build.
But real estate agents in the city are already feeling the pinch, with the bright-line test to double to 10 years after this Saturday.
Tall Poppy Real Estate agent Debi Pratt said investors had already threatened to pull their properties off the market if they were not sold before the changes take effect.
"We have had three investors pull their property from the market, or they've indicated that they'll have to if we can't get them unconditionally sold by when this kicks in," she told Newstalk ZB.
"The reason for that is they've owned them for five or six years. So, they will now have to get them sold before the bright-line test changes, or they're going to have to hold.
"We've already, just in our tiny world in three hours - lost three listings, so they're causing more pressure to go onto supply."
Pratt feared the Government's shake-up would have the opposite effect for first-home buyers, making it even more competitive.
"This time last year, there were about 2000 properties on the market in Christchurch and at the moment there's 1200," she said.
"If you've got to withdraw houses, even if it's 100 properties - you've still just gone and made it worse by nearly 10 per cent."
Reinz acting chief executive Wendy Alexander said some first-home buyers in the South Island were still being priced out of the market, and she was surprised the caps hadn't moved in booming markets.
Outside Christchurch, the price caps have not shifted in the Queenstown-Lakes, Waimakariri or Selwyn districts.
"Currently, only 12 per cent of properties sold in the Queenstown-Lakes District fall below the $650,000 threshold and only 11 per cent fall below the $550,000 threshold in the Selwyn District," she said.
"There's not a significant percentage of properties below that, so it's still going to create challenges to enter the market," she told Newstalk ZB.
But in the Buller District, the property market is soaring - and house sales jumped nearly 50 per cent last year.
Buller District mayor Jamie Cleine says people love that you can buy an entire house for what you'd pay for a deposit in Auckland.
He said the area is attracting both active retirees and young professionals.
And change is on the cards for Nelson, where the over-priced market is about to slow.
Deputy Mayor Judene Edgar is optimistic the Government's package will make housing more affordable in the sunny spot.
She said the average house price is about $700,000, well above residents' incomes and it is no surprise the city is in the top 25 per cent for unaffordable housing.
Edgar said more housing in the centre and new greenfield developments would plug the gap.